With development of communications technologies, data security draws more attention from people. In conventional technology, security of data is usually guaranteed by encrypting the data. For requirements of authentication during decryption, usually, while encrypted data (that is, ciphertext) is stored into a storage device, a key is also stored in a specific form. Therefore, if both the ciphertext and the key are stolen, data leakage is very likely to be caused. Hence, in the prior art, an encryption solution is further provided. In this solution, a single device characteristic, for example, information, such as an International Mobile Equipment Identity (IMEI), of a device, may be used as an encryption means to encrypt data of the present device, so as to prevent information from being leaked in a case in which content of the present device is copied. Because device characteristic information is not stored, no information leakage would be caused even if ciphertext is lost.
During a process of researching and implementing the prior art, it is found by the inventor of the present disclosure that the foregoing solution is only suitable for storage of a single device, but is not suitable for a case in which a plurality of devices shares a piece of ciphertext, and if the devices are lost together, that is, the ciphertext and a key are lost together, information leakage is also caused, and consequently, security of the existing solution is also not high enough.